Reaction Mechanism for the Diastereocontrolled Synthesis of Phosphorothioate DNA by the Oxazaphospholidine Approach

Abstract

Reaction mechanisms for the diastereoselective synthesis of deoxyribonucleoside 3′-cyclic phosphoramidites as well as dinucleoside phosphite intermediates by the oxazaphospholidine approach were analyzed by means of ab initio molecular orbital calculations at the HF/6-31G* level. These reactions are essential for the diastereoselective synthesis of phsophorothioate DNA.